As the story goes, the man was stationed in Germany in 1960 when his sergeant told him to buy a Rolex before he left, because they were the best watches ever made. He listened to his superior and bought the watch. Not only that but he kept ALL the paperwork, box, and everything. 

He took the watch to Antique Roadshow expecting a modest return on investment, but he was floored when he found out the real value of his item. The valued his watch at $65,000 - $75,000, that's not bad for purchasing the watch for $120 in 1960.